How to upload image to server (using POST) which return json in Windows Phone 8.1 RT?

Question

I am making an app which can upload image to a server (the server works well), and I use this method to upload my image to it, but when I get the respond from the result, it return a null string, can you explain for me what did I do wrong.

I followed this method: How to upload file to server with HTTP POST multipart/form-data

HttpClient httpClient = new HttpClient();
MultipartFormDataContent form = new MultipartFormDataContent();
form.Headers.ContentType = new MediaTypeHeaderValue("multipart/form-data");
byte[] bytes = await Converter.GetBytesAsync(storageFile);
form.Add(new ByteArrayContent(bytes, 0, bytes.Count()), "\"upload-file\"", "\"test.jpg\"");
HttpResponseMessage response = await httpClient.PostAsync("my-url", form);
response.EnsureSuccessStatusCode();
httpClient.Dispose();
string sd = response.Content.ReadAsStringAsync().Result;
Debug.WriteLine("res: " + sd); // this return a null string

The request return like this:

--a81d2efe-5f2e-4f84-83b9-261329bee20b Content-Disposition: form-data; name="upload-file"; filename="test.jpg"; filename*=utf-8''%22test.jpg%22

��Ivg?�aEQ�.��(��9%�=��>�C�~/�QG$�֨��(�`��QE��Z��

Can you help me please!

P/s: Here is my convert method

        public static async Task<byte[]> GetBytesAsync(StorageFile file)
        {
            byte[] fileBytes = null;
            if (file == null) return null;
            using (var stream = await file.OpenReadAsync())
            {
                fileBytes = new byte[stream.Size];
                using (var reader = new DataReader(stream))
                {
                    await reader.LoadAsync((uint)stream.Size);
                    reader.ReadBytes(fileBytes);
                }
            }
            return fileBytes;
        }

score 0 · Answer 1 · answered Apr 12 '16 at 07:15

0

This might help

 private async Task<string> UploadImage(StorageFile file)
            {
                HttpClient client = new HttpClient();
                MultipartFormDataContent form = new MultipartFormDataContent();
                HttpContent content = new StringContent("fileToUpload");
                form.Add(content, "fileToUpload");
                var stream = await file.OpenStreamForReadAsync();
                content = new StreamContent(stream);
                content.Headers.ContentDisposition = new ContentDispositionHeaderValue("form-data")
                {
                    Name = "fileToUpload",
                    FileName = file.Name
                };
                form.Add(content);
                var response = await client.PostAsync("my-url", form);
                return response.Content.ReadAsStringAsync().Result;
            }

answered Apr 12 '16 at 07:15

Archana

3,135
1
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"fileToUpload" is file to bytes or to Base64string? – iamatsundere181 Apr 12 '16 at 07:19
I hope that is just a name. Actual content of the file is content = new StreamContent(stream); that you will be adding to form.Add(content); – Archana Apr 12 '16 at 07:25
Why "hope", it means you did not use it? – iamatsundere181 Apr 12 '16 at 07:29
Nope. I said in answer "it might help" – Archana Apr 12 '16 at 07:31
I cant test whether it works or not. OpenStreamForReadAsync() method is there in System.IO namespace. You have to add that namespace. – Archana Apr 12 '16 at 09:01
Thanks for your help, but maybe I need more supports, howerver, thank you!! – iamatsundere181 Apr 12 '16 at 09:21
You want image to send in bytes or base64String? – Archana Apr 12 '16 at 09:22
Let us [continue this discussion in chat](http://chat.stackoverflow.com/rooms/108907/discussion-between-iamatsundere181-and-archana). – iamatsundere181 Apr 12 '16 at 09:32

score 0 · Answer 2 · answered Apr 15 '16 at 06:43

0

Use ByteArrayContent instead of StringContent. That Should work. And if you are expecting a stream-response you should use ReadAsStreamAsync instaed of ReadAsStringAsync.

answered Apr 15 '16 at 06:43

Chirag Shah

971
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6
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How to upload image to server (using POST) which return json in Windows Phone 8.1 RT?

2 Answers2